The long-term goal of this Research Training Program is to develop a new generation of pediatric endocrinologists who will be equipped to carry out innovative and scientifically rigorous patient-oriented and laboratory-based research related to diabetes mellitus in children for this new 21st Century. One of the needs for this Program is the critical shortage of academic pediatric endocrinologists in diabetes research which has been emphasized by the organizations such as the American Diabetes Association, the Juvenile Diabetes Research Foundation, and the Pediatric Academic Societies. In addition, the Program recognizes the important new opportunities for advancing diabetes research in children provided by such recent scientific advances as the Human Genome Project and the successes in islet transplantation and production of biomechanical and bio-engineered islets. The Program will support Trainees during up to 2 years of research training at the fellowship level. The Training faculty includes 19 scientific mentors from the Children's Hospital and the U Penn School of Medicine who have outstanding credentials and active research programs and training records. These mentors will supervise Trainees' in basic laboratory research and/or patient-oriented research projects related to diabetes in children. Research opportunities will include three major areas of basic research 1) Signal Transduction: Mechanisms of Hormone Action; 2) Regulation of Pancreatic beta-cell Function and Development; and 3) Genetic Approaches to Diabetes and Endocrine Diseases. Patient-oriented research opportunities will include the areas of 1) Islet Immunology, Transplantation, and Regulation; 2) Obesity and Insulin Resistance, 3) Diabetes Complications; and 4) Diabetes Epidemiology and Biostatistics. The Program includes training in all aspects of research, including biostatistics, bioethics, molecular biology, etc. The Program is strongly supported by access to a superb range of institutional resources, including the CHOP GCRC and the UPenn DERC. Request is made for 3 Trainee slots in this Program each year.